There is inconvenience in that a driver must continue to depress a brake pedal in a situation such as a long-time stopping state, a signal waiting state, etc. during driving of a vehicle and hence the driver's fatigue can be increased.
In order to solve such inconvenience, the AVH is applied to a vehicle.
The AVH is one of driver's convenience devices, which can maintain a stop state even when the driver releases a brake pedal after the driver depresses the brake pedal and hence the vehicle is stopped at D/R/N stage.
When the driver depresses an accelerator pedal at D/R stage after the vehicle is stopped by the AVH, the AVH function is released and the vehicle starts.
At this time, when the AVH function is released by the accelerator pedal, release of the AVH function is performed after the amount of depression of the accelerator pedal and the generation of torque on a power train side are checked in consideration of roll-back on a steep road.
For reference, the power train means that in a case of a hybrid vehicle, it comprises an engine, a motor and a transmission, whereas in a case of a typical internal combustion engine vehicle, it comprises an engine and a transmission.
However, during releasing the AVH function, a feeling of being caught occurs (i.e., feeling that the vehicle starts sluggishly) and feeling of rushing (i.e., feeling that the vehicle starts suddenly) due to external factors such as distribution of friction force between frictional materials and disks of a brake system and torque fluctuation of the power train. This is because it is difficult to precisely match the time point at which torque of the power train is generated by means of the accelerator pedal and driving force is increased with the time point at which braking force is extinguished.
If there is a means capable of releasing hydraulic pressure of the brake without raising torque of the power train under the condition of running on a flat road or a downward inclined road, it is possible to select a manner of releasing the AVH according to the driver's intention, thereby preventing the above-mentioned phenomena such as feeling of being caught, feeling of rushing, etc.
That is, if there is another means for releasing braking force resulting from operation of the AVH by a separate means after maintaining creep torque in addition to the means for allowing the AVH function to be released when the acceleration pedal is depressed and the torque of the power train is raised, it is possible to prevent the above-mentioned phenomena such as feeling of being caught, feeling of rushing, etc.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.